This invention concerns a cable guide structure which protects cables such as telephone cords, tubes or cables (hereafter called simply xe2x80x9ccablesxe2x80x9d) when they are connected to a revolving chair with casters on its legs in such a way that they trail freely on the floor. More specifically, when electricity is supplied from the exterior to a revolving office chair with casters on its legs to provide power for a built-in health appliance such as an electric massager, shoulder heater or shiatsu device, this cable guide structure protects the power supply cable from being run over by the casters or getting wound around the legs of the chair. The scope of the invention is not limited to office chairs only; it could also be applied when a person seated in a chair is being monitored for pulse rate or other physiological data, or when a cable is providing audio or video signals to a seated person.
An example of a revolving office chair with casters provided in the prior art is shown in FIG. 1 of U.S. Pat. No. 5,247,925 (FIG. 7 herein). This revolving chair 500 moves freely about the floor with the rotation of casters 540. Its post 520 is able to rotate 360 degrees about its center in the horizontal plane. It is customary for a person seated in such a revolving chair with casters to move about the floor while seated in the chair. At such times, if the chair has a built-in electrical appliance to which a power supply cable 550 is connected, the cable may be trapped under casters 540 (see FIG. 8) so that the casters lock up, and the cable may be damaged. Or, as is shown in FIG. 9, casters 540 may run over the cable, so that it becomes entangled among legs 530. This will limit the mobility of the chair and may cause damage to the cable.
A prior art design to alleviate these problems, which was proposed in U.S. Pat. No. 5,371,920, is shown in FIG. 10. It provides a cylindrical guard (cylindrical portion 137) around each caster (wheel assembly 119) so that the power supply cord cannot be run over. Another solution was offered in U.S. Pat. No. 4,025,099, shown in FIG. 11. A panel (flipper plate 30) is provided on the front of each caster to keep the cable away from the wheels so that it cannot be run over. Panel 30 is attached by hinge pin 31 so that it hangs down under its own weight. Its front end 33, then, is normally in contact with the floor so that it can lift up the cable.
However, the prior art designs for office chairs do not address the problem illustrated in FIG. 8, which occurs when several of the casters are locked simultaneously by being trapped in a cable lying on the floor. When one end of the cable is attached to the seat of the chair and the other is attached to a wall outlet, the cable""s freedom of movement is limited. When the casters move, then, the cable can get hung up on them, which can result in the casters becoming locked. If people in an office frequently move their chairs around, this will happen again and again. When it does happen, the plug may be pulled out of the wall outlet, or the chair which is stuck may tilt on the fulcrum provided by the casters and fall over.
Or, as is shown in FIG. 9, the connection site 511 where the cable is attached to seat 510 may end up, when the seat rotates on post 520, on the side of the chair opposite socket 522 and plug 551. When this happens, the portion of electrical cord 550 which is on the floor can easily become entangled among legs 530 so that it hinders the free movement of casters 540. In the prior art solutions discussed above, then, cable connection site 511 lacks a stabilized directionality with respect toward socket 552 and plug 551; thus the danger that the cable will become entangled on casters 540 remains unaddressed.
This invention is developed in order to eliminate the problems discussed above. The object of this invention is to provide a cable guide structure which would stabilize the direction of an electrical or other cable trailing onto the floor from a revolving office chair with casters on its legs or some other revolving and movable body.
Another object of this invention is to provide a cable guide structure which would make it difficult for the cable and casters to interfere with each other regardless of the movement of the casters when the cable extends from a revolving, movable chair with a built-in electrical appliance in such a way that it can move freely on the floor.
For this purpose, the cable guide structure according to this invention has a supporting arm which holds the electrical cable virtually horizontal in the space above the legs of the chair so that it cannot be run over by the casters. This supporting arm is mounted to the post of the chair in such a way that it can revolve around the post. The arm supports the cable in the space above the legs and leads it out a given distance from the post, where it is allowed to drop from the end of the arm to the floor. This distance is somewhat beyond the radius of the rotational path of the chair legs. Thus the cable which runs out from the chair is guided along the supporting arm until it is allowed to drop to the floor a sufficient distance beyond the casters. When the chair revolves or moves, the portion of the cable which is on the floor will not be run over by the casters. In addition, this invention also provides a caster sweeper unit for each caster to sweep away the portion of the cable which is on the floor. It thus offers two separate types of cable guide structures to prevent the cable from being run over by the casters